438 Bending Moment and Shear. may be shewn to be parabolic, as at/s (Fig. 393), or greatest near the axis, while on the contrary the greatest bending stress is furthest from the axis, as shewn at A. |/s x area of section = total shear *~A f s total shear load on section ana js = -%---------------------:---------- area of section In very short beams this stress should be considered, till finally, in rivets and pins, the shear is almost pure. We will now examine the distribution of Bending Moment and Shear Load under various conditions of support arid load. (Seep. 922.) I. Cantilever with Concentrated Load* (Fig. 394).—AB is the beam and W the load, the latter having a leverage over tJte= w section A of W x / ton feet: at section D of W x f /, and so on. The Bending Moments at various sections may therefore be repre- sented on the base line ab by downward ordinates, thus : AtA»W/xi atD=W/xf Atc=W/x| atE=W/x^ and at B= nothing; and these ordinates are shewn at /^, hjr and b. The Shearing Force is caused by the reciprocal action of W and Rt, and will equal W upon any section between A and B. For regularity we shall always consider the force an the right side of * Weight of beam is not taken, unless stated.